Repeatability of measurements of the initial distribution volume of glucose in haemodynamically stable patients

Effects of cardiac output on the initial distribution volume of glucose in the absence of fluid gain or loss in pigs

The initial distribution volume of glucose (IDVG) has been reported to be a surrogate marker of cardiac preload. However, the relationship between cardiac output and IDVG is not fully understood. We investigated the effects of cardiac output on IDVG in the absence of fluid gain or loss in pigs.

MATERIALS AND METHODS

Thirteen pigs were anesthetized and allocated to either the modified cardiac output group (m-CO group, n = 10) or the control group (control group, n = 3). In the m-CO group, CO was sequentially modulated from high CO (high CO) to two grades of low CO (low CO-1 and low CO-2) with dobutamine and propranolol with lidocaine, respectively, in the absence of any apparent change in basal fluid volume status. Thermodilutional CO and IDVG were measured at each CO condition. The IDVG was measured according to a one-compartment model with 2 g glucose. The same parameters were measured in the control group using the same time schedule as for the m-CO group but without inotropes and at a stable CO state. Thereafter, 250 ml of 10% dextran were infused over 15 min to compare the effects of a preload-dependent increase in CO on IDVG measurements to the effects of the pharmacological modification of CO. Data were expressed as the mean ± SD. Statistical analysis was performed with repeated measures ANOVA followed by Dunnett's test. Pearson's correlation test was also used. A P value of <0.05 was considered to indicate statistical significance.

RESULTS

In the m-CO group, where CO increased to 147.2 ± 26.7% of the baseline CO value in the high CO state and decreased to 65.9 ± 11.0 and 37.3 ± 14.4% of the baseline CO value in the low CO-1 state and the low CO-2 state, respectively, the IDVG did not change as CO was modified. IDVG significantly increased in response to volume loading of dextran in the control group. There was no correlation between the IDVG and CO in the m-CO group when there was no fluid gain or loss (r = 0.097, n = 40, P = 0.554), but the IDVG was well correlated with CO in the control group with volume loading (r = 0.764, n = 18, P = 0.0002).

CONCLUSION

This study suggests that the IDVG is dependent on the central extracellular fluid volume and not on cardiac output.

The pleth variability index as an indicator of the central extracellular fluid volume in mechanically ventilated patients after anesthesia induction: comparison with initial distribution volume of glucose

Background

The pleth variability index (PVI) has been demonstrated to be a useful, noninvasive indicator of continuous fluid responsiveness. Whether PVI can be used to assess the changes of intravascular volume status remains to be elucidated.

Material/Methods

Using correlation analysis and receiver operating characteristic (ROC) curves, we sought a correlation between PVI and the initial distribution volume of glucose (IDVG), evaluating PVI as an indicator of the central extracellular fluid volume after anesthesia induction in patients undergoing elective abdominal surgery.

Results

Strong negative correlations existed between IDVG and PVI (r=−0.72), IDVG, and pulse pressure variation (PPV) (r=−0.73), and between IDVG and systolic pressure variation (SPV) (r=−0.53), P<0.01. Strong positive correlations existed between PPV and PVI (r=0.66), PVI and SPV (r=0.49), and between PPV and SPV (r=0.59), P<0.01. The areas under the ROC curve of IDVG, PVI, and SPV were significantly different from the area under a reference line. The optimal cutoff values (followed by sensitivity and specificity in parentheses) comparable to PPV over 11% as the threshold of hypovolemia were IDVG 94.5 mL/kg (75%, 100%), PVI 13% (91.7%, 77.8%), and SPV 7% (41.7%, 100%).

Conclusions

Our results show that strong correlations exist among IDVG, PVI, PPV, and SPV in the evaluation of volemia. PVI can serve as a useful, noninvasive indicator of continuous central extracellular fluid volume for those patients not requiring invasive hemodynamic monitoring, but needs attention to changes in intravascular volume status for optimal fluid management.

Basic and clinical assessment of initial distribution volume of glucose in hemodynamically stable pediatric intensive care patients

Background

Initial distribution volume of glucose (IDVG), which is not associated with significant modification of glucose metabolism, has been proposed as an indicator of the central extracellular fluid volume status in adults. However, data on IDVG in children are lacking. This study examined pharmacokinetic data on IDVG in children and compared IDVG with other clinical variables.

Methods

In total, 128 daily data sets from 60 consecutive pediatric intensive care patients (body weight ≥8.0 kg), consisting mostly of children undergoing cardiovascular surgery, were studied. Either 1 or 2 g of glucose based on body weight (approximately 0.1 g/kg) was administered. IDVG could not be determined from ten data sets from eight children because of body movement-associated glucose fluctuation during measurement. In the remaining 113 data sets from 55 children, IDVG was determined by applying the one-compartment model. Approximated IDVG based on the incremental plasma glucose level at 3 min postinjection (1-point IDVG), and approximated IDVG based on incremental plasma glucose levels at 3 and 5 min postinjection (2-point IDVG), were also calculated. Postoperative daily IDVG and the relationship between IDVG and cardiac output or circulating blood volume (CBV) were evaluated when data were available.

Results

Convergence was assumed in each glucose clearance curve. Mean indexed IDVG (IDVGI) of the first measurement in 55 children was 144 ± 22 (SD) mL/kg, which was associated with a plasma glucose disappearance rate (Ke-glucose) of 0.094 ± 0.033/min. Bias and precision were smaller between 2-point IDVG and standard IDVG than between 1-point IDVG and standard IDVG (−0.02 ± 0.13 L versus 0.07 ± 0.20 L, p <0.001). Postoperative IDVGI in 37 children after cardiovascular surgery increased daily on postoperative days 1–2 (p ≤0.011). Linear correlations were observed between IDVGI and indexed cardiac output (r = 0.588, n = 28, p <0.001) and between IDVGI and indexed CBV (r = 0.547, n = 25, p = 0.0047).

Conclusions

IDVG is a potential marker of fluid volume status in children, even though body movement-associated glucose fluctuation is a major limitation. Two-point IDVG is preferable to 1-point IDVG for approximated IDVG.

Corrected right ventricular end-diastolic volume and initial distribution volume of glucose correlate with cardiac output after cardiac surgery

PURPOSE

Appropriate adjustment of cardiac preload is essential to maintain cardiac output (CO), especially in patients after cardiac surgery. This study was intended to determine whether index of right ventricular end-diastolic volume (RVEDVI), corrected RVEDVI using ejection fraction (cRVEDVI), index of initial distribution volume of glucose (IDVGI), or cardiac filling pressures are correlated with cardiac index (CI) following cardiac surgery in the presence or absence of arrhythmias.

METHODS

Eighty-six consecutive cardiac surgical patients were studied. Patients were divided into two groups: the non-arrhythmia (NA) group (n = 72) and the arrhythmia (A) group (n = 14). Three sets of measurements were performed: on admission to the ICU and daily on the first 2 postoperative days. The relationship between each cardiac preload variable and cardiac index (CI) was evaluated. A p value less than 0.05 indicated statistically significant differences.

RESULTS

Each studied variable was not different between the two groups immediately after admission to the ICU. cRVEDVI had a linear correlation with CI in both group (NA group: r = 0.67, n = 216, p < 0.001; A group: r = 0.77, n = 42, p < 0.001), but RVEDVI had a poor correlation with CI (NA group: r = 0.27, n = 216, p < 0.001; A group: r = 0.19, n = 42, p = 0.036). IDVGI had a linear correlation with CI (NA group: r = 0.49, n = 216, p < 0.001; A group: r = 0.61, n = 42, p < 0.001), Cardiac filling pressures had no correlation with CI.

CONCLUSION

Our results demonstrated that cRVEDVI and IDVGI were correlated with CI in the presence or absence of arrhythmias. cRVEDVI and IDVGI have potential as indirect cardiac preload markers following cardiac surgery.

Neither dynamic, static, nor volumetric variables can accurately predict fluid responsiveness early after abdominothoracic esophagectomy

Background

Hypotension is common in the early postoperative stages after abdominothoracic esophagectomy for esophageal cancer. We examined the ability of stroke volume variation (SVV), pulse pressure variation (PPV), central venous pressure (CVP), intrathoracic blood volume (ITBV), and initial distribution volume of glucose (IDVG) to predict fluid responsiveness soon after esophagectomy under mechanical ventilation (tidal volume >8 mL/kg) without spontaneous respiratory activity.

Methods

Forty-three consecutive non-arrhythmic patients undergoing abdominothoracic esophagectomy were studied. SVV, PPV, cardiac index (CI), and indexed ITBV (ITBVI) were postoperatively measured by single transpulmonary thermodilution (PiCCO system) after patient admission to the intensive care unit (ICU) on the operative day. Indexed IDVG (IDVGI) was then determined using the incremental plasma glucose concentration 3 min after the intravenous administration of 5 g glucose. Fluid responsiveness was defined by an increase in CI >15% compared with pre-loading CI following fluid volume loading with 250 mL of 10% low molecular weight dextran.

Results

Twenty-three patients were responsive to fluids while 20 were not. The area under the receiver-operating characteristic (ROC) curve was the highest for CVP (0.690) and the lowest for ITBVI (0.584), but there was no statistical difference between tested variables. Pre-loading IDVGI (r = −0.523, P <0.001), SVV (r = 0.348, P = 0.026) and CVP (r = −0.307, P = 0.046), but not PPV or ITBVI, were correlated with a percentage increase in CI after fluid volume loading.

Conclusions

These results suggest that none of the tested variables can accurately predict fluid responsiveness early after abdominothoracic esophagectomy.

Comparison of Initial Distribution Volume of Glucose and Intrathoracic Blood Volume During Hemodynamically Unstable States Early After Esophagectomy

STUDY OBJECTIVE

We have reported that initial distribution volume of glucose (IDVG) measures the central extracellular fluid volume in the presence of fluid gain or loss without apparent modification of glucose metabolism. We hypothesized that IDVG has a close relationship with intrathoracic blood volume (ITBV). We examined whether IDVG can correlate with ITBV during hemodynamically unstable states early after esophagectomy.

DESIGN

Prospective clinical study.

SETTING

General ICU.

PATIENTS OR PARTICIPANTS

Twelve consecutive hypotensive patients who required volume loading during the first 10 postoperative hours after admission to the ICU.

INTERVENTIONS

Indexed ITBV (ITBVI) and cardiac index (CI) were measured by single transpulmonary thermodilution technique using 10 mL of cold saline solution. Indexed IDVG (IDVGI) was then determined by the administration of 5 g of glucose and calculated by applying a one-compartment model. Three sets of measurements were performed: immediately after admission to the ICU, during hypotension, and after subsequent volume loading.

MEASUREMENTS AND RESULTS

When hypotension developed, stroke volume index (SVI), central venous pressure, and ITBVI were decreased but IDVGI and CI were not. All these variables were increased after volume loading. IDVGI was correlated only slightly with either ITBVI (r2 = 0.23) or SVI (r2 = 0.38) but moderately with CI (r2 = 0.61).

CONCLUSIONS

Results does not support that IDVGI can be equivalently used as an alternative measure of ITBVI or SVI, but IDVG may be clinically relevant as a measure of the fluid volume affecting CI even during hemodynamically unstable states after esophagectomy.

Blood glucose increments as a measure of body physiology

The initial distribution volume of glucose (IDVG) can be calculated from the arterial plasma glucose level between 3 and 7 min after a bolus intravenous infusion of 5 g glucose. Ishihara and colleagues have investigated the value of IDVG over the past decade. Although IDVG is simple and cheap to measure, there have been several very different proposals regarding what it should be used for. The most interesting and logical correlate is that between IDVG and cardiac output. A recent study showed that it does not matter much whether the calculation of IDVG is based on blood or plasma samples.

Initial distribution volume of glucose can be approximated using a conventional glucose analyzer in the intensive care unit

Introduction

We previously reported that initial distribution volume of glucose (IDVG) reflects central extracellular fluid volume, and that IDVG may represent an indirect measure of cardiac preload that is independent of the plasma glucose values present before glucose injection or infusion of insulin and/or vasoactive drugs. The original IDVG measurement requires an accurate glucose analyzer and repeated arterial blood sampling over a period of 7 min after glucose injection. The purpose of the present study was to compare approximated IDVG, derived from just two blood samples, versus original IDVG, and to test whether approximated IDVG is an acceptable alternative measure of IDVG in the intensive care unit.

Methods

A total of 50 consecutive intensive care unit patients were included, and the first IDVG determination in each patient was analyzed. Glucose (5 g) was injected through the central venous line to calculate IDVG. Original IDVG was calculated using a one-compartment model from serial incremental arterial plasma glucose concentrations above preinjection using a reference glucose analyzer. Approximated IDVG was calculated from glucose concentrations in both plasma and whole blood, using a combined blood gas and glucose analyzer, drawn at two time points: immediately before glucose injection and 3 min after injection. Subsequently, each approximated IDVG was calculated using a formula we proposed previously.

Results

The difference (mean ± standard deviation) between approximated IDVG calculated from plasma samples and original IDVG was -0.05 ± 0.54 l, and the difference between approximated IDVG calculated from whole blood samples and original IDVG was -0.04 ± 0.61 l. There was a linear correlation between approximated and original IDVG (r² = 0.92 for plasma samples, and r² = 0.89 for whole blood samples).

Conclusion

Our findings demonstrate that there was good correlation between each approximated IDVG and original IDVG, although the two measures are not interchangeable. This suggests that approximated IDVG is clinically acceptable as an alternative calculation of IDVG, although approximated and original IDVGs are not equivalent; plasma rather than whole blood measurements are preferable.